Rick Santorum’s victories in Alabama and Mississippi prolonged the Republican primary contest yet again, all but destroyed Newt Gingrich’s continuing claim to a credible candidacy, and relegated Mitt Romney to an embarrassing third-place finish in states where he had seemed to be gaining ground.

But Santorum’s Deep South exacta did nothing to alter the ironclad reality that whichever Republican ultimately gains the nomination, he will beat Barack Obama in Mississippi and Alabama in the fall—just as any Republican would beat any Democratic presidential candidate that fate might devise in those two states as far into the future as the clearest crystal ball can see.

“You really shouldn’t look for any soon turnaround,” said Hodding Carter III, the veteran Mississippi journalist and Democratic activist, reflecting on an entrenched trend now nearly 50 years old. “The reason is that there’s just no base on which to build. Increasingly, the political structure at all levels is dominated by Republicans, with one officer-holder who’s black—a Democratic congressman in some district or another.”

Jimmy Carter, from neighboring Georgia, was the last Democrat to win Alabama and Mississippi, in 1976, and that had “more to do with who was still alive among whites” than with any other factors, said Hodding Carter, who edited his family’s newspaper in Greenville, Mississippi, before becoming President Carter’s State Department spokesman. “In Carter’s instance, you still had at least a carryover of people who remembered why they had been Democrats for economic reasons, who were old-fashioned, mostly hill-country people who were never going to get right on race—in the sense of voting for somebody instead of against somebody—but who were enough traditional Democrats, as the saying went, that ‘My granddaddy would turn over in his grave if I voted Republican.’

“Increasingly, the political structure at all levels is dominated by Republicans, with one officer-holder who’s black—a Democratic congressman in some district or another.”

“And every year, another group of those people die,” Carter added, “and another group thinks, Oh, the hell with it. Why am I even bothering?”

There are many reasons for the Deep South’s emergence as a reliable 21st-century political monoculture (just as it was an agrarian monoculture in centuries past), beginning with the backlash against the 1964 Civil Rights Act, which, as Lyndon Johnson correctly foresaw, delivered the South to the Republican Party. The subsequent creation of congressional districts with high enough concentrations of black voters likely to elect black officials left the remaining districts overwhelmingly white and unlikely to elect anyone but a Republican, so that, over time, Democratic office-holders at the local level switched parties or bit the dust.

If there is any doubt that the Deep South remains a place apart, a recent survey by Public Policy Polling, a Democratic-leaning outfit, found that 52 of Republican respondents in Mississippi said that Barack Obama was a Muslim, while only slightly more managed to concede that interracial marriage should be legal.

In the aftermath of President Carter’s 1980 loss to Ronald Reagan, Hodding Carter noted, progressive southern Democrats could at least take comfort at the presence of young comers like Bill Clinton of Arkansas. But not even Clinton and his running-mate Al Gore, “both professing Baptists,” as Carter put it, could carry the deepest South in 1992 or 1996, and in 2000, “for God’s sake, Al couldn’t carry Tennessee, or Arkansas for that matter.”

In fact, Carter said, “the loss of Arkansas as a reliable Democratic state is perhaps a more devastating statement than others, because for years it had such quality people,” from Senators J. William Fulbright, Dale Bumpers, and David Pryor to Bill Clinton himself.

Could anything change the status quo?

“There are those who say, ‘Well, we could do it if the national party would only moderate its stands on the social issues,’” Carter said. But that would require the national Democratic Party to put at risk the support of its core liberal constituencies in the hope of winning crossover voters it might never get in the end.

Carter sees one other possibility: If a devastating economic collapse had occurred long enough before the 2008 election to make it clear that Barack Obama had nothing to do with it, “it might have been possible that a national Democrat could have re-taken this election now—if, of course, that national Democrat had been willing to run a Teddy Rooseveltian campaign against the ‘malefactors of great wealth,’” he said. But he added, “The fact is, denial is just an incredible thing when it comes to white Southerners being able to fake themselves out on the economy, and to focus on what it is they actually needed, as opposed to what they resent.”